Rotary pump and motor hydraulic transmission



5 Sheets-Sheet 1 Dec. 15, 1953 K. 1. POSTEL ET AL ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Filed 001;. 14, 1947 I JmF E om 9 mm L 5 Law m m wt ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Filed Oct. 14, 1947 5 Sheets-Sheet 2 INVENTORS KEN N ETH I. POSTEL JOSEPH P. HORVATH BWOZM ATTORN EY 5 Sheets-Sheet 3 INVENTORS KENNETH l. POSTEL JOSEPH P. HORVATH ATTORNEY K. 1. POSTEL ET AL ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Dec. 15, 1953 Filed Oct. 14, 1947 Dec. 15, 1953 ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Filed Oct. 14, 1947 5 Sheets-Sheet 4 INVENTORS KEN NETH l. POSTEL JOSEPH P. HORVATH ATTORN EY Dec. 15, 1953 K. 1. POSTEL ET AL ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Filed Oct. 14. 1947 5 Sheets-Sheet 5 INVENTORS KEN N ETH I. POSTEL JOSEPH P. HORVATH ATTORN EY Patented Dec. 15, 19.53

ROTARY PUMP AND MOTOR HYDRAULIC TRANSMISSION Kenneth I. Postel and JoseilhP. Horvath, Detroit,

Mich., assig-nors to Vickers Incorporated, Detroit, Mich, a corporation of Michigan Application October 14, 1947', Serial No. 779,732

1 Claim.

This invention relates to power transmissions, particularly to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and an.- other as av fluid motor.

The invention is more particularly concerned with. a power transmission system incorporating a. fiuid pump and motor construction of the type having a rotary cylinder barrel provided with axial cylinders and pistons reciprocal therein which abut against a rotating thrust plate, the axis of which is inclined to the axis of rotation of the cylinder'barrel.

It is. a general object of this invention to provide a fluid energy translating device of this'type which is of simple and reliable construction, suitable for low cost manufacture, and capable of highv performance over long periods of service.

It is a more particular object of this invention to provide for a transmission of the type mentioned, wherein a closed circuit is formed, a replenishing pump circuit which will provide fluid to replace leakage and maintain the pistons against the thrust plate at one controlled pressurewhile providing fiuid under pressure at a different controlled pressure for the operation of servo controls.

It is also an object of this invention to provide anoveland economical means for efficiently cooling the transmission.

It is a further object of this invention to provide means for substantially reducing sounding board effects during operation of the transmission and cooling system.

It is another object of the invention to provide a protective shroud for the transmission.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompany i-ng drawings wherein a preferred form ofthe present invention is clearly shown.

In the drawings:

Figure l is a sectional view of a preferred form Figure '1 is a partial. sectional view takenon.

line ':'-.-'i of Figure 6.

Figure. 8 is an exploded sectional view of the replenishing pump shown in FigulT? 5.

Figure 9 is a top view of'the micarta disc shown in Figures and 8.

Figure 10 is a partial front view of the valve block.

Figure 11 is a sectional view taken on line HT. of Figure 1.

Figure 12 is a sectional view taken on line iZ-IZ of Figure 11.

Figure 13 is a view taken on line l3l3 of Figure 14.

Figure 14 is a front view of the fan.

Figure 15 is a side view of the yoke.

Figure 16 is a partial sectional view of the shroud surrounding the pump casing and control mechanism for shifting the yoke.

Figure 17 is an end view of the transmission.

Referring now to Figure 1 there is shown a power transmission comprising a reversible vari-. able displacement pump section indicated by the numeral I0 and a fixed displacement motor sectionindicated by the numeral l2. Thepumpand motor sections ii] and- 12 are provided with casings M and It, respectively, which by means ofsuitable upper through bolts 18 and lower through bolts 19 have their open ends held in abutment against a valve block member 2!! which forms a partitionbetween the two casings.

The casings may preferably be die cast of a suitable aluminum alloy or other non-ferrous metal. Surrounding the casings I and I6 is a tubular shroud formed in two bell shaped sections 22 and 24 which are connected with their largest open ends in abutting relationship by the bolts l8.

As shown in Figure 17, rubber grommets 21' are placed between the shrouds and the casings, at the ends thereof where the through bolts iii are inserted, in order to avoid metal to metal contact.

The shrouds may be stamped from suitable'thin sheet metal andare provided with indentations of pyramidal shape, indicated by the numeral 29, where the bolts l8 and is are inserted. The shroud protects the casings and transmission from impact damage. The indentations provide walls for strengthening the shroud adding to the protective'qualities of the latter. In addition, the shroud serves to supply an air space between the casing and the shroud which provides part of an air cooling system hereinafter described.

The through bolts I8 serve to connect the casings in abutting relationship to the valve block and also to maintain the two shroud sections with their largest open ends in abutting relationship with each other. The through bolts l9, however, serve only to connect the two casing sections to each other as the nuts threaded at each end pass through holes made in the lower indentations of the shroud sections and abut the ends of the casings rather than the shrouds.

A pump shaft 26 and a motor shaft 28 are journalled on bearings 30 and 32 in their respective housings and on needle bearings 34 and 36, the latter of which are mounted in a through hole 38 of thevalve block 20-. Suitable oil seals 45) are 3 provided where the shafts 26 and 28 extend through the casings I4 and I6.

Mounted on the pump and motor shafts and 28 are pump and motor cylinder barrels and 43, respectively, which are in driving engagement with the shafts by means of loose fitting spline sections indicated by the numerals 44 and 46. The shafts are maintained in position by means of retaining washers 48 which fit into grooves provided in the casings and engage the outer surfaces of flanges 58 formed on the shafts and by retaining springs 52 engaging the inner surfaces of the spline shaft sections. Retainer washers 54 fitted into grooves formed in the cylinder barrels hold the springs 56 in abutment against the inner surfaces of the splined sections. Retainer washers 56 cooperate with the retainer washers 48 for positioning the shaft bearings 36 and 32 and the oil seal 40.

The cylinder barrels 42 and 43 are provided with a plurality of cylindrical holes 58 within which pistons 66 are reciprocably mounted. The outer edges of the pistons are preferably rounded and are adapted to drivably engage the inner races 62 of thrust bearings 64 and 65. The motor thrust bearing 66 is positioned in a mounting box 68 provided in the motor casing member IS, the angle of inclination of which is fixed. The pump thrust bearing 64 is mounted in a yoke ID, the angle of inclination of which may be shifted from neutral to either side of neutral so as to vary the volume of the pump from zero to maximum and also reverse the direction of flow to the motor.

As shown more clearly in Figures 2, 11, 12, and 15, the yoke 70 is provided with arms i l and I2 which are respectively mounted on pintles I3 and I4 extending into the pump casing. The pintles I3 and I4 are mounted within bosses formed on opposite sides of the pump casing I4 with the aid of snap rings '55. A pintle lock '68 connected to the arm 72 of the yoke I0, which is longer than the arm II, and butt welded to the inner end surface of the pintle I4 rigidly connects the arm I2 to the pintle E4 so that rotation of the latter will change the angle of inclination of the yoke I0. The pintle 14 which is longer than the pintle '52 extends through a hole provided for that purpose in the shroud.

The extended portion of the pintle I4, as shown in Figures 2 and 16, extends into a control box TI provided with a removable cover I8. The control box TI is mounted by suitable screws to bosses I9 provided for that purpose on the valve block which extend through the pump and motor casing shrouds. The valve block 20 is provided with four of the bosses I9, two each on opposing sides of the valve block for alternative installation of the control box.

Referring now to Figures 2 and 16, within the control box I? one end of an arm is rigidly connected to the end of the pintle I4. The opposite end of the arm 83 is connected by a pin 3! to a hand wheel screw 82. One end of the pin BI is rotatably mounted in the arm 80 and the screw 82 is threadable through the opposite end of the pin BI. A handwheel control 83 is rigidly fastened to the screw 82. An indicator dial 84 suitably fastened to the arm 88 so as to be movable therewith is viewable through a hole 85 provided in the cover '58 (Figure 17) Thus, by turning the handwheel control 83 the yoke I6 may be shifted and its angle of inclination determined by reading the indicator dial 84.

For the purpose of filling the transmission, a

4 combined funnel and expansion tank 86 is provided having a removable cover 81. The funnel 86 has a tube 83 threadable into any one of three passages 89, 98, or 9| provided in bosses 92, 93,

, and 94 located respectively on the valve block 2B, the pump casing I4 and the motor casing I6. The passages as, 80, and 9| open into a fluid supply space indicated by the numeral 95. As shown in Figures 2 and 5, the tube 98 is shown threaded into the boss 92 located on the valve block 20 while the passages 99 and SI in the bosses 93 and 94 are closed by suitable plugs 99.

There is thus provided three different, convenient locations for filling the transmission.

A filter screen 55'! mounted in a rubber grommet 98 is mounted by means of the grommet in the funnel 86.

Valve plates 99, shown in Figure 3, provided with arcuate shaped ports I00 and IOI extending from face to face corresponding to similar shaped ports I02 and I93 formed in and extending through the valve block (Figure 5) are journalled on the pump and motor shafts 26 and 28 against the opposite surface areas of the valve block to provide bearing surfaces against which the pump and motor cylinder barrels 42 and 43 rotate. The valve plate ports I00 and I Ell cooperate with individual ports I04 (Figure 4) one at the end of each cylinder 58 of the cylinder barrels 42 and 43.

The opposite surfaces of the valve block 20 are provided with a pin I05 (Figures 6 and 10) insertable in a hole I06 (Figure 3) of the valve plate for preventing rotation of the latter.

Due to the fact that the porting of the valve block is adapted to form a closed system as the cylinder barrels rotate against the valve plates, provision is made for priming the pump during initial operation and for replenishing the main pump at a controlled pressure during normal operation.

Thus, in Figures 5 and 8, there is shown a replenishing pump, indicated generally by the numeral IIJ'I, which is mounted in a vertical passage I08 extending from the bottom of the valve block 20 to the shaft hole 38. The pump I61 is comprised of a piston I09 which, on the upward stroke, draws fluid into a fluid chamber H0 and which expels fluid from this chamber on the downward stroke through a check valve III mounted in a retainer H2. The retainer H2 is keyed to the casing at I I3. A spring I I4 serves to bias the piston I09 upwardly and a spring I I5 serves to bias a Micarta disc II 6 (Figure 9) downwardly so as to seat the latter upon the retainer II2 on the downward stroke of the piston I 09. The piston I IE9 is operated on the downward stroke by an eccentric cam II I formed on the left end of the pump shaft 26. The spring I I4 operates the piston I 09 on the upward stroke.

On the upward stroke of the piston I09 the Micarta disc I I6 lifts and. uncovers ports I I8 in the retainer H2 connected to an undercut portion H9 of the retainer I I2. A plurality of ports I20, one of which is shown in Figure '7, connect the fluid supply space 95 to the undercut portion H9. Thus, the fluid supply space 95 is connected to the chamber IIO when the Micarta disc I I6 lifts and uncovers the ports I I8 in the retainer IIZ but is blocked from communication with the chamber II I! when the disc II 6 seats. The diameter of the "Micarta disc I I6 is slightly less than the diameter of the chamber IIO so that when the disc lifts, fluid flows around the disc into the chamber.

A fluid chamber 12 I *isformed at'the bottom :of the valve black .20 by .means 10f a plate 'I 22 having a plurality of recesses 1233, said plate being suitably bolted to the valve block. Fluid is can pelled by the pump 211W through the check valve I I I to the chamber .121 on the downward stroke of the piston 1B9.

Chamber 521 .is connected to two vertical fluid passages I24 and I15 located on opposite sides of :the hole 1138 (Figures -6 and 1). The passage I24 intersects the valve block arcuate port 102, .and the passage .12 intersects the arcuate port 1%.. Mounted :in the passages iii and .125 are duplicate check valves lifiand i2? biased'to'the closed position "by means of :duplicate springs 1 2.8 and 1 38 of predetermined resistance.

The fluid chamber 121 is also connected to a hole 132 within which is mounted an accumula- :tor piston I34 biased to the pcsitioneshown by a spring I35. Located .alove the upper portion 0f the piston, as shown, are a plurality of ports I38 connecting the hole I32 :to theiiiuid supply space 1-95. Another plurality of "ports Hit also connect the upper portion :of therhole I32 to the .iluidrsupply space95. flihepiston I34, in cooperation with the spring 1.315, is :also adapted to .act as a replenishing relief valve and will by-pass pressure fluid from the :pump 1 6:? through the ports 138 to the fluid supply space 85 when the bottom portion of thezpiston its cracks over the ports 138. A servo "port M2 constructed in a boss I of the plate 1.22 is connected to the fluid chamber I21. The servo-port 142 is closed by :a plate M6 screwed to the valve block 2t when servo controls are not "used in connection with theyoke 70.

The replenishing pump piston 1% is provided withan .undercutportion 141 which is connected to 'the extreme upper portion of therchamber -I iii). The undercut portion 14? is connected to the central portion of the valve block shaft hole 38 when the :pump piston 1&9 is at the top of its stroke as shown in Figure 5. Any entrapped air in the upper portion of "the replenishing pump chamber no is bled to the fluid supply space .95 by means of through grooves M9 formed on onposite sides of the shaft hole 38 and grooves .15I ("Figure 10) formed in the opposite faces-of the valve :block fitthe latter of which connect to the fluid supply space 95..

The valve block 2G is also provided with pressure passages I48 and b which are closed by plates 1.52 and P54 suitably screwed to the valve block when a pressure control for changing the angle of inclination of the yoke I0 is not used.

The pressure passages M8 and 55%,165980- tively, intersect the arcuate valve block ports I02 and 103.

Duplicate relief valve assemblies, indicated generally by the numerals I55 and ,IE'Z, .are mounted in passages IE9 and I61 located above the pressure control passages Hit and 15b (Figures 5 and '7) in the valve block 26 The :relief valves are adaptedto relieve excessive pressure fluid from the pressure port to the supply port of the valve block depending upon which side ofneutral the yoke "I0 is located.

The transmission is provided with ,a cooling system by mounting a fan 156 on the pumpshaft 26 forrotation therewith and locating the same I in .an opening 158 provided in the right end of the shroud section'ZQ (Figures'l, 14, 16, and'l'l). The fan I56 may preferably :be stamped from suitable sheet metal so as toiorm angularly disposed blades 160 and .air flow passages 162 as shown in Figure 1c. The fan I56 is provided with a hub I64 which may be spot welded thereto and which has a hole IE6 proportioned for rigidly fastening the fan 1-56 on the pump shaft .26 (Figures 13 and 1.4). When fastened .on the pump shaft 26, the Tan 1156 willrotate therewith to take in cool air from the pump end and blow the same through the air space formed between the shroud and the casing, said air space being indicatedby the numeral 163, and out an :opening 11% formed inthe motor shroud section 2.4. Inithis way, the casings are cooled and likewise the oil within the casing.

Provision has also been made for deadening the sound caused by operation of the transmis sion and cooling system. The two shroud sections are connectedto the pump and motor cas ings and to the valve block by means of the two upper through bolts I3. In order to avoid metal to :metal contact, the rubber grommets .21 are placed between the casings and the shrouds where the upper through bolts 13 are inserted.

"Itshould be noted that the lower through bolts .iS'pass-throughholes I72 in the pump andrmotor shrouds and that they serve only to connect the casings to the valve block 26. The bolts 19 do not have any contact with the :pump and :motor mission and cooling system, the irmer surfaces of the shroud sections are substantially covered with a suitable sound deadening material indicated by the numeral 174.

It should also be noted that the yoke 5-6 is adapted to not only :be shifted by the hand wheel shown :in Figures 2 and 1.0, but that the same may be shifted in "the conventional manner by connecting :a suitable pressure control to one of the pressure passages use or 15s or by connecting a servo operating control "to the servo port M2.

The transmission is provided with mounting leg-s 116 fastened to the end of the lower through bolts by means of nuts 118.

In operation, the pump is initially primed by the replenishing pump 19]. Fluid is withdrawn by the replenishing pump on the upward stroke :of :the piston 109 from the supply space in the casings to the fluid chamber 1 Iii in the pump 101. The supply space :95 is connected to the chamber 1.110 byzmeans ofqthe fluid ports .120, the undercut portion 1 19 of the retainer I i2, and the fluid ports 118. The lifting of the disc Son the suction stroke of the piston its uncovers the ports 1m and permits fluid to flow around the disc-to the chamber l1 c. On the downward-stroke of the piston 1.69 the disc I it seats on the retainer 11,2 blocking the ports 113. The piston Its forces fluid from the chamber III! through the check valve III to the chamber 121 at the bottom of the valve block 28. The check valve spring 128 has less resistance than the accumulator spring 36 and fluid from the pump It? :is directed by "means of the vertical passage 12:4 to the inlet .port I32 of the valve block 39. The pressure created at the outlet port 1.11.3 of the valve block which is connected to the vertical passage will maintain the check valve I2! in the passage 525 seated. As the pump cylinder barrel 42 rotates, some of the pistons 63 in the cylinders 53 thereof will be forced toward the valve block 29 by means of the inclined inner race 62 of the thrust bearing 64. Fluid will be forced from these cylinders by the pistons to the opposing cylinders of the motor cylinder barrel. The opposing pistons of the motor cylinder barrel will be forced in drivable engagement with the thrust plate 62 of the motor section. As the pistons of the motor cylinder barrel reciprocate, the motor cylinder barrel will rotate, thus rotating the motor shaft 28 connected thereto. The remainder of the pistons Within the motor cylinder barrel 33 will be forced inwardly toward the valve block by the motor thrust bearing 62 forcing fluid into the opposing pump cylinders containing the pistons shifting away from the valve block on their suction stroke. Consequently, a closed circuit is created by the valve block porting and the opposed cylinder barrels rotating against the valve plates. The angle of inclination of the pump and motor thrust bearing determines the length of stroke of the pistons within the cylinder barrels and consequently their fluid displacement. By rotating the hand wheel 83 to shift the yoke 19 towards the neutral position the stroke of the pump pistons become shorter and consequently its fluid displacement is decreased. It follows, that when the fluid displacement of the pump is decreased that the speed of the motor is proportionately decreased. At the neutral point of the yoke 79 the pistons within the pump cylinder barrel do not reciprocate and the motor becomes stalled.

If the yoke I is shifted in the opposite direction from this neutral position the arcuate ports I02 and I03 of the valve block are reversed in their function of inlet and outlet ports. When the yoke IE3 is shifted to the opposite side of neutral, fluid is admitted during the initial priming operation, from the replenishing pump to the arcuate port I 03 throu h the vertical passage I and the check valve I21 mounted therein. The check valve I26 in the vertical passage I24 remains seated.

During operation, one of the relief valves I will serve to relieve excessive pressure fluid from the pressure side of the pump to the inlet side depending upon which side of neutral the yoke Ill is located.

During operation, any leakage in the closed system is made up by the replenishing pump I01. Replenishing fluid is supplied to the inlet side of the pump at a pressure equal to the by-pass pressure, determined by the setting of the spring I36 of the accumulator piston I34, minus the drop in pressure across one of the check valves I26 and i2? determined by the springs I28 or I30. Thus, when servo controls or pressure controls are not associated with the yoke '59, the accumulator will be loaded with fluid at a pressure determined by the setting of the spring I36 and the output of the replenishing pump will be by-passed to the supply space 95 th ough the ports I38. Any leakage in the closed system is thus supplied to the arcuate inlet port of the valve block at the by-pass pressure minus the drop in pressure across the check valve connected to the arcuate inlet port. The pistons reciprocating within the cyilnder barrels are likewise held against the thrust bearings 62 at this pressure.

When a servo control is used in conjunction with the transmission it may be connected to the servo port I42. The servo control may be operated at the controlled by-pass pressure as determined by the setting of the spring I 36 and the pistons in the cylinder barrels will be maintained against the inner race 62 of the thrust bearings at another controlled pressure. This latter controlled pressure, as stated above, is the by-pass pressure minus the drop in pressure across the inlet check valve I2I or I21.

It should be noted that the pump and motor casings, the cylinder barrels and the valve block, may preferably be die cast resulting in mass production economy. The shroud and fan may be stamped from suitable thin sheet metal.

It should also be noted that the die cast transmission is also provided with an efficient and economical coolin system with which is associated an efficient means for deadening sound board effects. The shrouds not only provide an air space for the cooling system, but in addition provide adequate protection from impact damage to the transmission.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claim which follows.

What is claimed is as follows:

A self-contained hydraulic power transmission comprising a two-section casin within which is a main jump and motor, a stationary valve block forming a partition between the casing sections common to the pump and motor for controlling the admission and exhaust of fluid to and from the pump and motor, said casing sections and 7 and bolts mounted in the casing sections, valve block and shroud bolt holes serving to connect the two casing sections in abutting relation to the valve block and also to maintain the two shroud sections with their open ends in abutting relationship with each other.

KENNETH I. POSTEL. JOSEPH P. HORVATI-I.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,044,838 Williams Nov. 19, 1912 1,080,282 Kellogg Dec. 2, 1913 1,250,554 Crain Dec. 18, 1917 1,308,844 Ferris et a1 July 8, 1919 1,312,701 Magic et al. Aug. 12, 1919 1,539,616 Williams May 26, 1925 1,628,603 Ferris May 10, 1927 1,752,134 Woodman Mar. 25, 1930 1,924,017 Bedford Aug. 22, 1933 1,961,592 Muller June 5, 1934 1,967,838 Norris July 24, 1934 2,283,516 Tyler May 19, 1942 2,409,374 McGill Oct. 15, 1946 FOREIGN PATENTS Number Country Date 14,791 Great Britain June 26, 1913 

